The Artificial Pancreas, Issues and Update.The artificial pancreas (closed loop) consists of three components...a continuous glucose sensor, algorithms that translate glucose levels into an insulin release response, and an insulin pump.Current glucose sensors are subject to mechanical failures, delays, and poor calibration.However, new sensors are under development to reduce these problems.Insulin pumps are adequate, but most deliver insulin subcutaneously.The normal beta cell releases insulin directly into the circulation within seconds, responds to both positive and negative rates of glucose change, and turns off rapidly.In contrast, insulin absorption from subcutaneous sites is slow, resulting in insufficient insulin during meals, and post-prandial hypoglycemia as insulin is still absorbed.Most algorithms, to compensate for this problem, employ Model Predictive Control (MPC) or Proportional-Integral-Derivative + Feedback (PID-FB).Currently, these algorithms, similarly, result in good overnight control, but have difficulty controlling meals and exercise.Ancillary approaches include patient-provided, pre-meal glucose (Hybrid), glucagon pumps, and various methods to improve insulin absorption kinetics from the subcutaneous site.Overall, progress is both rapid and promising.